The invention is based on an actuating drive with an electric motor and control electronics.
By means of the references U.S. Pat. No. 4,384,223, DE 33 14 412 C2, and DE 196 54 352 A1, it is widely known to dispose electrical interference suppression means inside metallic electric motor housings, adjacent to the collectors and associated brushes of so-called collector motors, and to connect these interference suppression means to the brushes and also to the metallic electric motor housings. In order to connect the interference suppression means to the metallic electric motor housings, resilient tabs protrude from so-called brush holder plates that support the brush holders and these tabs can, for example, be embodied at their free ends in the form of tapering claws. This has the advantage that a favorable electrical contact is produced, for example through the production of scoring tracks due to relative movements of these claws in relation to the electric motor housing during assembly. In an interference suppression circuit disclosed by the U.S. reference U.S. Pat. No. 4,384,223, capacitors are used as interference suppression means. In this instance, two capacitors are connected in series and the contact disposed in the electric motor housing is connected to both capacitors. The respective other connection of each of the capacitors is respectively connected to one of the brushes. An interference suppression circuit of this kind is also known by the name xe2x80x9cCy interference suppression circuitxe2x80x9d. In contrast, in the examples according to DE 33 14 412 C2 and DE 196 54 352 A1, a brush connected to an interference suppression circuit is electrically connected to the electric motor housing in as low-ohm a fashion as possible according to the method xe2x80x9cMasse des Electromotorgehxc3xa4uses an einem Pol des Gleichspannungsnetzesxe2x80x9d [Grounding the Electric Motor Housing to a Pole of the Direct Current Network], wherein the direct current network can be the electrical system of a vehicle. In such a connection of the electric motor housing to a brush, there is most often the limitation that the electric motor can only be operated in one rotation direction, which is sufficient, though, in a pump drive motor for a piston pump, for example of a hydraulic vehicle brake system or a windshield wiper drive motor.
The reference DE 42 42 641 A1 has disclosed an actuating drive with an electric motor that has a metallic electric motor housing. A shaft with an armature and collector, as well as brushes and a brush holder plate, and with control electronics for the electric motor. The electronic and electric components are connected to a printed circuit board and the printed circuit board protrudes at right angles to the shaft and, adjacent to the brush holders, protrudes into a cross section of the electric motor housing, and outside the electric motor housing, is protected by a control electronics housing. The actuating drive has, for example, a worm drive and is used, for example, to move a sliding sunroof. Accordingly, the electric motor must operate in two different rotation directions, which is achieved by means of the control electronics. The control electronics are also set up in such a way that the sliding sunroof mentioned above can also assume selectable intermediary positions between structurally possible end positions. The electric motor is switched off in the end positions. Because this electric motor has a collector and brushes, it can be necessary to provide an interference suppression circuit in the actuating drive, for example of a type used in the prior art. The interference suppression means can be added, for example, to the control electronics and can be fastened, for example, to the printed circuit board.
The actuating drive according to the invention, with an electric motor and control electronics, has the advantage that during assembly of the electric motor, which includes the sliding together of the electric motor housing and the brush carrying plate through the addition of the printed circuit board, the metallic electric motor housing can be connected in an electrically conductive manner to an interference suppression circuit, for example embodied as a Cy circuit whose interference suppression means are contacted by the printed circuit board of the control electronics.
Advantageous improvements and updates of the actuating drive are possible by means of the measures taken hereinafter.
The actuating drive has the advantage that the printed circuit board can take up a relatively large amount of space inside the electric motor housing because only one cutout is needed per se in the printed circuit board in order for the thinnest rotating component of the electric motor, namely the shaft, not to collide with the printed circuit board.
The features set forth herein produce a favorable anchoring of the contact spring, installed according to the invention, in an otherwise normally provided brush carrying plate. After the installation of the brush carrying plate, the printed circuit board can be aligned in relation to the shaft, moved along this shaft toward the brush carrying plate, and mounted, wherein a contact tab then protrudes through an opening in the printed circuit board in order to be soldered to an associated strip conductor.
Other features set forth herein disclose an alternative embodiment to the embodying means set forth above. The featured opening in the brush carrying plate can be produced by means of a relatively simply embodied tool, and thus the contact spring is inserted into this opening in a subsequent assembly step.
Still another feature produces the advantage that after being inserted into the opening, the contact spring is secured in the axial direction in a positively engaging fashion.
Yet another feature produces the advantage that even before the assembly of the actuating drive, the contact spring can be connected to the printed circuit board and soldered to a strip conductor. In this respect, the soldering can be carried out at the same time as the production of other required soldered connections of the control electronics.
In lieu of the relatively narrow openings in the brush carrying plates mentioned in the preceding exemplary embodiments, the brush carrying plate is now given a relatively large opening through which the contact spring can be introduced into the electric motor housing, for example in a contactless manner.
While still another feature produces a favorable anchoring of the contact spring to the printed circuit board so that the desired contact force that acts in a tilting fashion on the contact spring does not lead to detachment from the printed circuit board.
Other features produce the advantage that during assembly of the electric motor, the resilient end of the contact spring that produces the contact does not stick out during the passage through the brush carrying plate and during insertion into the electric motor housing, as a result of which the insertion of the contact spring can be carried out.
Yet another features produce the advantage that before and during assembly of the electric motor, the contact spring is largely protected from damage or from bending that would impair the production of contact.
Other features set forth produces the advantage that for example when the contact spring is fastened in a tilt-free manner to the printed circuit board, the resilient free end is sufficiently pressed against the electric motor housing. The starting ramp achieves the fact that toward the end of the insertion of the contact spring into the electric motor housing, the freely resilient end is moved into the contact position in a radial direction in relation to the electric motor housing.